While it did work in turning on subtitles automatically on youtube, even when choosing the non-autogenerated option from the dropdown options it still will turn on autogenerated captions. Additionally it basically auto opens the caption menu from the tool bar and makes selections which results in the full menu opening in front of your video every time you click a new video, which ends up being more distracting than just clicking c to turn on captions yourself honestly, and that setting sticking for the following video at least.